Dengue in Puerto Rico

The Dengue Branch of the U.S. Centers for Disease Control and Prevention is located in San Juan, Puerto Rico. Although travel-associated dengue infections do occur and a number of dengue outbreaks have been detected in the continental United States, most dengue cases among U.S. citizens occur as a result of endemic transmission in some U.S. territories, such as Puerto Rico.

Puerto Rico has experienced epidemic dengue activity periodically since 1963. Dengue continues to be endemic in Puerto Rico, with three to nine thousand suspected dengue cases reported during non-outbreak years.  Since 1990, there have been three large epidemics of dengue. In 1994 there were 24,700 suspected dengue cases reported and in 1998 there were 17,000 cases reported.   More recently, in 2007, 10,508 cases of suspected dengue infections were reported. Of these, half were hospitalized and one third reported having a hemorrhagic manifestation.

In Puerto Rico, control of dengue in the 1970-1980s relied on application of pesticides and household inspections. It became evident that these approaches were unsustainable. The focus shifted toward citizen involvement in the control of vector “breeding sites” in yards and homes, personal protection through use of insect repellent, and education on recognition of symptoms with the need to seek timely medical care. Control of dengue today remains a challenge, though innovative methods of mosquito control are being evaluated in Puerto Rico and worldwide.

The Dengue Branch has been conducting island-wide, laboratory-based passive dengue surveillance (PDSS) in Puerto Rico, in collaboration with the Puerto Rico Department of Health (PRDH) for more than 30 years. Dengue fever and dengue hemorrhagic fever are reportable diseases by law in Puerto Rico. The PDSS relies on healthcare provider--initiated requests for diagnostic testing, and submission of serum samples accompanied by a Dengue Case Investigation Report (DCIR) from suspected dengue case-patients to the CDC Dengue Branch Laboratories. The specimens are processed free of charge and tested in accordance with an algorithm, and results are mailed and faxed to the submitting provider. Data from the DCIR, which include patient demographic and clinical information, are entered by CDC into an electronic data system. A weekly summary of PDSS data is disseminated by CDC and used by the PRDH to plan public health interventions and coordinate its vector control activities on the island:
Also available in Spanish/en español

The weekly summary report shows how many cases of suspected dengue infections are reported each week in Puerto Rico.  It compares this number to the number of cases reported each year since 1986.  Outbreaks are announced when the number of suspected dengue cases surpasses the 75th percentile based on historic data (1986-2008).  The report also provides information about laboratory confirmed cases of dengue including the geographic distribution of cases (i.e., at the county or municipal level) and what dengue serotypes are in circulation.